**8. Future prospects**

Beside the fertilizer or amendment properties of digestate, nowadays there are some other ways to utilize it. These new methods are very creative and make the possibility of proper utilization of digestates with different quality.

A new promising alternative of the digestate utilization is its use as solid fuel after drying. Kratzeisen et al. (2010) used liquid digestate originated from silage maize co-digestion with different field crops and animal residues. After drying the digestate, the water content of pellets made was 9.2-9.9%. Their mechanical durability fulfilled the requirements of standards for pellets. Moreover, the calorific value of these pellets was similar to the calorific value of wood. Therefore digestate fuel pellet seems to be a good alternative fuel for wood.

Another interesting possibility of digestate utilization is the using of digestate effluent to replace freshwater and nutrients for bioethanol production. Gao & Li (2011) found that ethanol production was enhanced with digestate effluent by as much as 18% comparing to the freshwater utilization.

Digestate can be separated to liquid and solid fraction. Liquid fraction is suitable for irrigation and it has high N and K content. Solid fraction contains a great amount of volatile solid and P (Liedl, et al., 2006) and – by its fertilizer effect – has also high biogas and methane potential, therefore it could be used as a co-ferment for anaerobic digestion (Balsari et al., 2009)
